Gallocyanine dyestuffs



Patented Dec. 1, 1931 STA E PATENT OFFICE ER-NS1,HUG- AND HEINRICH iwEnmiNBERG, or NEU-ALLscnwIL, NEAR BASEL,

SWITZERLAND, ASSIGNORS' '10 DURANID &

- LAND HUGUENIN s. 'A., or; BASED, swi'rziia- I GALLOGYANINE nynsrurrs No Drawing. 'Applieat-ionfiled November 20,1923, Serial No. 320,745, and in Germany November 26, 1927.

' The present inyention'relates to new dyestuffs of the gallocyanine series, more par ticularly tocoinpomids having in their free state the probabie general formula:

' oo-A 7 wherein A stands for a hydroxy, alko xy, amino, or arylamino group,- with a compound of the formula:

whereinthe litteree X, R, and R have the same meaning, asabove, under such condi-- tions as are usual inthe manufacture of gallo'cyanine dyestufi-'s-.-

The products thus obtainable constitute dark powders soluble in strong sulphuric. acid with blue to violet colorations, yielding bright violet to blue shades when used in printing with chrome mordants'.

Compared to the corresponding Well known products, which in place of do not contain any substituent, the new dyestuffs show, in discharge printing, an increased' resistance to'hydrosulphi-te and other reducing agents; 1 v.t In 7 the U. S." p I 895,635 :the" dyestuff from nitrosodiethylmeta-ch loraniline and gallamide and the corresponding leuco compound are described; also in Friedlander IX, page 255, there are patent specification mentioned gallo'cyanine dyestufiswhich re.- 7

suit by condensation, of-nitrosodiethyl-metaamino-phenol-ethers I with; gallic acidor der rivatives thereofl But neither in one in the other case it is said that the dyestufis' in question withstand hydrosu-lphite;

In any case,.from these two publications, the new technical efiect of the present invention cannot be concluded, namely the fact that gallo'cyanine dyestufi's which, are derived from a meta-substituted alkyl aniline and which therefore have asubstituentyin meta position with respect to the. alkylamino group,-Jwithstand hydrosulphite and other reducing agents better than gallocyanine dyestuffs, which in substituent. v p

For printing purposes it will often be advantageous' to previously transform the new dyestu-fl's into thecorresponding leuco dethe said positionhave no rivatives (in View of their better solubility),

for" example by means of zinc hydrochloric acid, which leuco compounds are easily reo'xidized on the fibre;- and' it is to be understood that alsofthese leuco derir ati-Wes are Within the scope of the presentinvention.

The following examples will illustrate the parts being by weight:

invention, without limiting it thereto, the

. Example 1 I i In 500 parts of methyl alcohol, 20,6.wparts of gallic acid anda quantity of thenaphthalene disu-lphonic 'salt of nitros0diethyl' rneta toluidine which corresponds to 34,6} parts of the nitroso compound of 100 per cent strength are heated to boiling until the nitroso, compound has disappeared. The dyestufi,-. which separates after cooling, is filtered ofl"and washedwith alcohol and ater. It forms acrystalline, powder which is somewhat soluble in alcohol and less soluble "inc in water, dissolving in concentrated sulphuric acid with a blue coloration. In its free state it probably corresponds to the formula:

N O U1Hu O l I ou I 00011 7 mordants it yields bright violet shades showing satisfactory fastness to hydrosulphite under the conditions of discharge printing.

E mample 2" A mixture of-54 parts-of nitrosomonoethylmeta-tolu'idine hydrochloride, parts of gallamide and 300 parts of inethyl'alcohol is boiled until no more fnitroso compound present. The dyestuff thus obtained is sparingly soluble in water and alcohol. The shade of its solution in concentrated sulphuric acid is violet. VVh'en printed upon cotton with clirome' mordants it yieldsbrigtt red-violet shades showing satisfactory fastness to hydro'sulphite underthe conditions of discharge printing. j Especially strong shades of the same dyestufi can be obtained by reducing it to its leuco compound, for instance by means of z'inc'and hydrochloric acid, and using this leuco compound in the printing process, reoxidation taking place on the fibre.

Vhilst theisomeric dyestulf (nitrosoln'onoethyl-orthotoluidine gallamide) shows in discharge printing an alteration of its shade tothe blue side, the present dyestufl' does, un-

der the same condition, hardly change its shade at 'all. 1

Example 3 i 7 ,From parts of gallic acid and 100 parts of nitrosodimethyl-meta-toluidine in 600 parts .of methyl alcohol a gallocyanine dyestuff is preparedin the .usual way, which owing to its free carboxylic group is soluble in diluted alkali. This dyestuff is, for instance according to the processdescribed in U. S. Patent Specification No. 863,907,transformed by. reducing and splitting off of the vcarboxylic acid group into the leuco-compound of the corresponding gallocyanine derived from pyrogallol. (This latter in oxidized form is insoluble in dilute alkali.)

While the dyestuff from 'nitrosodimethylaniline and gallic acid wherein the carboxylic group has been split off and which has'been reduced) is wholly unsuitable for discharge printing, as it gives, owing'to decomposition," weak, dull shades, the present dyestufli' gives, under the same conditions, in discharge printing the same bright" violet shades as in direct printingg' v As furtherexamples the'follo'wing dyebeing also usable in form of their leuco stufls may be mentioned, which all show a good resistance to hydrosulphite The dyestuff which is obtained by heating the gallocyanine prepared according to Example 1 (nitr0s0diethyl-meta-toluidine-lgallic acid) in an alkaline solution whereby thezcarboxylic.group'is split OE, and which, for use in printing, may be advantageously reduced;

v tc blb When, printedhuponp pt h chrome The gallocyanme dyestuff ob una e y the action of nitrosotetrametliyl meta-phcnylcnediai'nine on gallumide, yieldingin chrome printing bluish-violet shades of good fastness to chlorine and soap;

The dyestufi' from" l-dimethyla minO-B- vwherein X means one of the following monovalent substituents; alkyl, NH alkyl-. or acetyl-substituted NHQ, R stands for an alkyl group, R for hydrogen or an alkyl group, and .Y forhydrogen, a free carboxyl group or one of the following substituted carboxyl groups; CONT-I CONH aryl and C00 alkyl, said productsconstituting valuable dyestufls for discharge printing, yielding bright violet to blue-shades when printed with chromium mordants and being usable in form of their leuco derivatives.

2. The herein described new gallocyanine dyestuffs having in their free state the probable general-formula:

wherein R stands for an alkyl group, R for hydrogen or an alkyl group and Y for hydrogen, a free carboxyl group or one of the following substituted carboxyl groups; CONH CONH 'aryl and COO alkyl, said products constitutingvaluabledyestuffs for discharge printing, yieldingbright violet to blue shades when printed with chromium mordants and livatives.

3.. The herein described new gallocyanine dyestufi's having in their free state the probable formula:

CH: OOH being valuable in discharge printing, yielding a bright blue violet shade when printed with chromium inordants and being also usable in form of its leuco derivative.

In witness whereof we have hereunto signed our names this 8th day of November ERNST HUG. HEINRICH WERDENBERG. 

